Pneumatic governors for liquid-fuel injection pumps



July 3, 1956 w. E. w. NICOLLS PNEUMATIC GOVERNORS FOR LIQUID-FUEL. INJECTION PUMPS Filed July 12, 1954 limited States Patent Q PNEUMATHJ GUVERNURS FOR LIQUID-FUEL INJECTION PUMPS Wilfrid Edward Walter Nicolls, Pinner, England, assignor to C. A. V. Limited, London, England Application July 12., 1954, Serial No. 442,855

1 Claim. (Cl. 123-440) This invention relates to a pneumatic governor responsive to the air pressure in the air-intake passage of a reciprocatory internal combustion engine, for controling the output of a liquid-fuel injection pump, the governor being of the type having combined with it an airbleed device serving to stabilise, or prevent flutter, of the governor when the pump is in or near the condition of minimum delivery, and the engine being of the kind which is provided with an air blower; It is desirable under some conditions to provide means for rendering the stabilising means inoperative when running the engine above a predetermined speed, and the object of the present invention is to enable this requirement to be met in a convenient manner.

A governor in accordance with the invention has combined with it a valve responsive to blower-air pressure for over-riding the action of the governor stabilising means.

In the accompanying drawings, Figure 1 is a diagrammatic view illustrating one arrangement of a fuel injection pump, pneumatic governor, and air-intake system of an engine, for which the invention is required.

Figure 2 is a sectional side elevation of a valve embodying the invention.

Referring to Figure 1, a known form of fuel injection pump a to which the invention is applicable includes a spring-loaded slidable rod b for regulating the pump output in response to the action of the governor. The latter comprises a hollow body part c mounted on the pump and divided into two compartments by a flexible diaphragm d (or piston) which is connected to one end of the control rod and is loaded by a spring 6. One compartment is open to the atmosphere. The other is connected by a pipe to the air-intake passage g of the engine it at a position associated with the throtle i or between the throttle and a blower in the said passage. The second compartment has combined with it a normally closed valve which can be moved to its open position by the diaphragm for admitting an air-bleed to the said compartment from the atmosphere, and thereby stabilising the action of the governor under low-pressure conditions in the said part of the air passage, that is to say when the control rod is moved by the diaphragm to or near the position of minimum fuel supply.

2,752,906 Patented July 3, 1956 In applying the present invention to a governor as above described and as illustrated by Figure 2, there is combined with the air-entrance side of the stabilising valve another hollow body part k which is divided into two compartments by a piston in which is loaded by a spring 11. One compartment is open to the outer atmosphere through bleed-holes 0 and stabilising air can normally pass from this compartment through an annular valve-seating p to the stabilising valve q. The other compartment is provided with a connection for a pipe r attached to the airintake passage of the engine at a point between the blower and the engine. Also on the piston is provided a closure member s which can be moved into contact with the said seating p when a predetermined pressure in the said passage is exceeded.

The valve q which is loaded by a spring t, is normally closed, but with increasing engine speed, the reduction of pressure in the air-intake passage effects a movement of the diaphragm d against the action or. the spring e towards the elongated stem u of the valve q and eventually moves the latter otr" its seating v for the admission of atmospheric air to the governor as above described.

So long as the blower air pressure remains below a given amount, the governor acts normally, but when this pressure is exceeded, the piston in moves the closure member s on to the seating p and so interrupts the admission of atmospheric air to the governor through the stabilising valve.

If desired the piston in may be substituted by a flexible diaphragm.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

A pneumatic governor for controlling the output of a liquid fuel injection pump whereby fuel is supplied to an internal combustion engine provided with an air-intake passage controlled by a throttle, and with an air blower situated in the air-intake passage at a position between the engine and throttle, comprising the combination with a movable member for varying the pump output of an air-pressure responsive member arranged to actuate said movable member, a hollow part through. the medium of which one side of said air-pressure responsive member is exposible to the air pressure in a part of the air-intake passage at the side of the blower remote from the engine, an air-bleed device operable by said air-pressure responsive member and arranged to admit atmospheric air to said hollow part for stabilising the action of said airpressure responsive member when said movable member assumes a predetermined position in which the quantity of fuel delivered by the pump is small, a valve controlling the supply of atmospheric air to said air-bleed device, and means responsive to blower-air pressure for actuating said valve to render said air-bleed device inefifective.

References Cited in the file of this patent UNITED STATES PATENTS 2,659,354 Nicolls Nov. 17, 1953 

